Wells are drilled to facilitate the extraction of hydrocarbons from a formation. During the drilling of a well, various drilling parameters can be monitored to adjust and optimize drilling operations. For example, sensors may be utilized to monitor parameters for steering a drill bit, measurements for the optimization of drilling efficiency, formation electrical resistivity, downhole pressure, direction and inclination of the drill bit, torque on bit, weight on bit, etc. During operation, sensor readings or data from the downhole sensors can be transmitted to the surface for monitoring, analysis, decision-making, and otherwise controlling drilling operations.
Drilling systems can transmit data from downhole sensors to a surface location for the above-mentioned purposes. For example, a drilling system can transmit data from a downhole location by introducing an electrical gap between the two ends of the drill string and emitting an electric field from the gap to transmit data to the surface. However, one drawback of conventional EM data transmission systems is that introducing an electrical gap into the drill string mechanically weakens the drill string, as the electrical gap is often created by sandwiching insulating materials between two separate metallic sections of one or more drill collars. During operation, the insulating material may be subject to torsional, compressional, and cyclical bending stresses under load. In some applications, low modulus insulating materials can plastically deform over time, while high modulus insulating materials may fracture, with both failures causing mechanical and/or electrical failure of the gap.
Further, EM data transmission systems may transmit at a low broadcast signal strength when operated on batteries, causing susceptibility to electrical noise that interferes with the detection and demodulation of the surface signal. Compounded with mechanical and/or electrical failure of the gap, as described above, battery operation can result in a severe reduction in transmitted signal strength. Therefore, what is needed is an apparatus, system or method that addresses one or more of the foregoing issues, among one or more other issues.